Fabrication of conductive nanostructures on a flexible substrate

ABSTRACT

Provided is a method of fabricating a continuous nanostructured material having an electrodeposited surface layer. A conductive master drum having a relief pattern on its surface that exposes only a portion of the master drum surface is immersed into a plating bath. An electrodepositable material is coated onto the exposed surface of the drum. A support material is coated over the deposited layer and the relief structure. Removal from the drum yields the nanostructured material.

FIELD OF THE INVENTION

This application relates to a method for fabricating nanostructuredand/or microstructured articles utilizing a continuous web-basedprocess.

BACKGROUND OF THE INVENTION

Microstructured and nanostructured devices, for example, can be used inarticles such as flat panel displays, chemical sensors, andbioabsorption substrates. Conventional methods for producingmicrostructured and nanostructured devices include molding a compliantmaterial using a pressing or printing technology to reproduce a moldedpattern, lithographic processes, and nanoimprint lithography.

Articles with microstructured and nanostructured topographies include aplurality of structures on a surface thereof (projections, depressions,grooves and the like) that are microscopic in at least two dimensions orhaving at least one dimension that measures less than a micron in thecases of a nanostructured topography. These topographies may be createdin or on the article by any contacting technique, such as, for example,casting, coating or compressing. Typically, these topographies may bemade by at least one of: (1) casting on a tool with a microstructured ornanostructured pattern, (2) coating on a structured film with amicrostructured or nanostructured pattern, or (3) passing the articlethrough a nip roll to compress the article against a structured tool ortextured master tool with a microstructured or nanostructured pattern.

While molding technologies may be used in combination with the masterreplication tool to make a continuous roll of product, the resolutionachieved with such procedure is generally limited to several microns andmay not be capable of producing nanoscale features needed for someapplications.

U.S. Pat. No. 6,375,870 discloses replicating a nanoscale pattern on theouter surface of a cylindrical roller. The nanoscale pattern istransferred from the cylindrical roller onto a substrate surface. Metalis coated into the depressions pattern formed on the substrate surface.Any material between the deposited metal is removed by either an etchingor lift off to realize the final metal structure.

SUMMARY OF THE INVENTION

There is a need for a continuous flexible nanostructured ormicrostructured sheet having a replicated base structure having at leasta partially conductive surface layer. Roll-to-roll manufacturingstructured material saves manufacturing costs and improves productionspeeds.

In an exemplary method of making a nanostructured article, a portion oftextured master tool having a relief pattern on a surface of the mastertool is immersed into a coating bath containing an electrodepositablematerial. The electrodepositable material is deposited onto the mastertool by either an electrolytic or electrophoretic deposition process. Asupport material can be applied to the surface of the master tool overtop of the deposited layer. Removal of the resulting structure from thetool yields the flexible nanostructured material.

The relief pattern may be one of a microscale relief pattern or ananoscale relief pattern. The relief pattern on the master tool caninclude conductive regions and non-conductive regions, and theelectrodepositable material is deposited on the conductive regions ofthe nanoscale relief pattern.

The master tool may be a cylindrical master drum, a master belt, amaster sheet or a master tile.

In an alternative embodiment of the inventive method, a carrier film maybe applied to the surface of the support material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an exemplary continuousnanostructured material according to an aspect of the invention.

FIG. 2 is a schematic representation of a fabrication system accordingto an aspect of the invention.

FIG. 3 is a flow diagram of an exemplary process for creating acontinuous nanostructured material according to an aspect of theinvention.

FIG. 4 is a scanning electron micrograph of the nanostructured materialfabricated according to Example 1.

FIG. 5 shows a schematic cross-section of the durable master describedin Example 2.

FIG. 6A is an atomic force micrograph of the nanostructured materialfabricated according to Example 2.

FIG. 6B is a scanning electron micrograph of the nanostructured materialfabricated according to Example 1.

FIG. 7 is a schematic representation of an alternative fabricationsystem according to an aspect of the invention.

While the above-identified drawing figures set forth several embodimentsof the invention, other embodiments are also contemplated, as noted inthe discussion. In all cases, this disclosure presents the invention byway of representation and not limitation. It should be understood thatnumerous other modifications and embodiments can be devised by thoseskilled in the art which fall within the scope of the principals of thisinvention. The figures may not be drawn to scale. Like reference numbershave been used throughout the figures to denote like parts.

DETAILED DESCRIPTION

The disclosure provides a method of making a continuous flexiblenanostructured or microstructured sheet having a replicated basestructure made of a first material and a partial or complete surfacemade of second different material. The second material may be eitherconductive or non-conductive. In an exemplary aspect of the invention,the second material may be electrolytically or electrophoreticallydeposited. Conductive materials can include metals, metal oxides,organic semiconductors or conductive polymers. Non-conductive materialsinclude non-conductive polymers and metal oxides. The metal oxides canbe any oxidized transition metal such as iron, aluminum, manganese,nickel, platinum, chromium, sliver, gold, copper, zinc and the like.

It is to be herein understood that the term “microstructure” includesfeatures that can be on the order of microns (from about 1 μm to about1000 μm or even larger) and nanostructure include features that can beon the order of nanometers (from about 1 nm to about 1000 nm). Thisdimension is the average smallest dimension of the features in the arrayand can be the diameter, for example, if the features are cylindricalposts.

The microstructures or nanostructures may be in the form of an array ona substrate. The array can be in the form of a regular array ofstructures, a random arrangement of structures, or a combination ofdifferent regular or random arrangements of structures. The structuredarray can be formed directly in the substrate or can be formed as anadded layer. While the terms nanostructure and nanofeature are usedpredominately in this disclosure, it should be understood that themethod disclosed herein is extendible to the fabrication ofmicrostructures or microfeatures.

Typical nanostructures can include post structures and ridge structures.Exemplary post structures can have one dimension substantiallyperpendicular to the substrate referred to herein as the height, h, andtwo much smaller dimensions (x- and y-dimensions). The smaller of thex-dimension and y-dimension is herein referred to as the width of thenanostructure. For example, the cross-section (or base) of the posts canbe circular where the x-dimensions and the y-dimensions are equal. Whenthe cross-section is circular and does not vary along the z-directionthe posts are cylinders. It is also possible that the x- andy-dimensions are equal but vary along the z-direction. In this case, theposts are conical. The conical shape may be truncated parallel to or atan oblique angle to the base. In fact, the cross-section of the base maybe any closed plane figure including, but not limited to a circle, anellipse, a polygon or any close curvilinear shape. Thus, truncatedcones, pyramids, and truncated pyramids are considered within the scopeof possible post structures. It is also contemplated, for example, thatthe posts can have a cross-section of a polygon such as a triangle,square, pentagon, etc. If the cross-section of the post structure is apolygon and it does not vary along its height, then the post can havethe shape of a prism. In fact, any shape of post is contemplated by thisdisclosure as long as the post has one long dimension and thecross-sectional area of the top of the post is approximately the same orless than the cross-sectional area of the base of the post.

An article having conductive microstructures on its surface orconductive nanostructures on its surface can be created by immersing atextured master tool having conductive regions and non-conductiveregions into a bath of an electrodepositable material. Once a sufficientthickness of the electrodepositable material has been deposited, themaster tool is removed from the bath and dried. A support material isapplied to the master tool. When the support material is removed fromthe master tool the electro deposited material is also removed yieldingthe desired article. The textured master tool can be in the form of acylindrical master drum, a master belt, a master sheet or a master tile.

Reference will now be made in detail to the exemplary embodiments,examples of which are illustrated in the accompanying drawings.

Referring to FIG. 1, a portion of an exemplary continuous nanostructuredmaterial 100 is depicted. By “continuous material” it is meant amaterial having a length (L) many times larger than its width (w). Forexample, continuous nanostructured material 100 can be many meters inlength (i.e., including hundreds or thousands of meters in length),while the width can be from about 2.5 centimeters to about 2 meters.

The continuous nanostructured material 100 is made up of an array ofnanostructures 105. The nanostructures 105 include an electrodepositedsurface layer 120 sitting atop a formed portion 130 on a carrier film orsubstrate layer 110. The electrodeposited material may be conductive(e.g. a metal, organic semiconductors or conductive polymers) ornonconductive. Alternatively, a metallic electrodeposited portion may beoxidized in a subsequent process to form a nonconductive metal oxideportion. For example, the nonconductive metal oxide portion can be madeof CuO, Ag₂O, CrO₂ or the like.

The nanostructured material 100 is prepared by an exemplary fabricationsystem and method as depicted in FIGS. 2 and 3, respectively, anddescribed in detail below.

An exemplary fabrication system 200 utilized to perform the continuousfabrication of an exemplary nanostructured article 100 having micron andsubmicron features is shown in FIG. 2. The fabrication system 200includes a master drum 210, having a relief pattern 212 formed thereon.In an exemplary embodiment, the relief pattern 212 is non-conductive andhas low surface energy surfaces 214, 215. The master drum is generallycylindrical in shape and may be made of an electrically conductivematerial (i.e. metal). The relief pattern on the surface of the drum maybe formed of non-conductive or dielectric material such as anon-conductive polymer, silicon dioxide, or a non-conductive carbonlayer and is the negative image of the nanostructured material beingproduced. For example, if the desired pattern on the finalnanostructured material 100 is periodic dots, then the relief structureon the surface of the drum is periodical holes. In an exemplaryembodiment, the master drum is made of a material with good electricalconductivity such as aluminum or other metal. Alternatively, the mastermay have an electrically conductive sleeve mounted on a non-conductivedrum core (not shown). For example, an ITO (indium tin oxide) layer 216may be coated at outer surface of master drum 210. In addition toproviding a conductive surface to facilitate the electro-deposition ofthe coating material, the ITO layer can also serve as a release layerbetween the master drum and the deposited material.

The master drum may be partially submerged into a coating bath 230. Thesurface 211 of the master drum is connected to one electrode, such ascathode 242, of a DC power source 246. Inside the coating bath, theother electrode, such as an anode 244, is connected to the same DC powersupply to form a complete electrical circuit.

In an exemplary embodiment, the master drum rotates in a counterclockwise direction 219. The coating bath contains anelectro-depositable coating material in a carrier solution such aswater. The electro-depositable coating material may be a metallicplating solution or a dispersion of an electrically conductive oligomeror polymer.

Electrodeposited metals can include gold, silver, tin, copper, nickel,tungsten, vanadium and various metallic coatings. For example, platingchemistries such as High Speed Nickel FFP Solution and ACR 150 GoldPlating Solution are available from Technic, Inc., (Cranston, R.I.) andCopper Gleam ST-901 is available from Rohm & Haas, Inc., (Philadelphia,Pa.).

The electrodepositable coating material is deposited on to the surface211 of the master drum in the openings in the relief pattern as themaster drum sweeps through the coating bath. The coating material doesnot deposit onto the surface 214 or sides 215 of the dielectric reliefpattern 212 on the surface of the master drum 210. The thickness of thecoating will increase with the residence time of the portion of masterdrum in the coating bath 230.

As the drum rotates, the deposited portion 213 will exit the coatingbath. A nozzle 250 will rinse any residual coating material from themaster drum. The cleaned portion of the coating drum may be dried byexposure to heat and/or blowing air.

A support material 260 is applied onto the surface of the master drum ata coating station 265. The layer can be added, for example, by coating,lamination, deposition, printing, or any other techniques known to thoseskilled in the art. Exemplary coating techniques to add the layer caninclude, for example, solution coating, dispersion coating, hot-meltcoating, knife coating, and dip coating. Lamination can include, forexample, heat lamination, photochemical lamination, and also can includearticle modification of the substrate or the layer or both.Post-lamination annealing can be done, if desired, to enhance adhesion.Vapor deposition techniques such as, for example, evaporative vapordeposition, sputtering, chemical vapor deposition, or plasma enhancedchemical vapor deposition are methods that can be used to add a layer tothe substrate and are within the scope of this disclosure.

The support material may be a thermoplastic polymer that flows atelevated temperatures but not at lower temperatures such as roomtemperature. Examples of thermoplastic polymers that can be used includeacrylics; polyolefins; ethylene copolymers such as polyethylene acrylicacid; fluoropolymers such as polytetrafluoroethylene and polyvinylidenefluoride; polyvinylchloride; ionomers; ketones such aspolyetheretherketone; polyamides; polycarbonates; polyesters; styreneblock copolymers such as styrene-isoprene-styrene; styrenebutadiene-styrene; styrene acrylonitrile; and others known to thoseskilled in the art.

Other useful support materials for forming a flexible nanostructuredmaterial include thermosetting resins that can be cured using acatalyst, heat, or photoexposure depending upon its chemistry, such as,for example, acrylates, polydimethylsiloxanes, urethane acrylates andepoxies. An example of thermosetting resins can be a photocrosslinkablesystem, such as a photocurable urethane acrylate, that forms a polymericsubstrate with microfeatures upon curing.

By tailoring the shape of the nanostructures and the materials used, thenanostructured material may be used as a wire grid polarizer, amicrolens, a bio-detection chip, a micromirror array, a metamaterial(negative index material), an electromagnetic shielding materials, ortouch screen components. For example, the biochip used for drugscreening and bio-detection based on enhanced stimulated Raman effect iscomprised of an array of sub-micron gold holes made on silicon chip.Conventional methods of making biochips can be expensive because ofprocesses used to make it and low yields. Making biochips by theinventive method disclosed herein can substantially lower themanufacturing cost at improved yields.

For some of these applications, the support material can be selected forits optical clarity. Optically clear support materials can includevisibly transmissive thermoset polymers such as, for example, acrylicpolymers, polycarbonates, polyesters (PET), polyester copolymers,polyethylene naphthalate polymers (PEN), urethane acrylates, epoxies,etc. Optically transmissive thermoplastic materials can also be used toform microlens or micromirror arrays. These materials can include, forexample, polycarbonates, polymethylmethacrylates, polyolefins,polyethylene acrylic acids, polyvinyl chlorides, polyvinylfluorides,ionomers, ketones such as polyetheretherketone, polyamides, polyesters,polyester copolymers, polyethylene naphthalate polymers (PEN), styreneblock copolymers and others known to those skilled in the art.

The support material coats the drum surface and fills in any area of therelief structure that was not coated with the electrodeposited materialto produce the formed portion 130 of the nanostructured material 100.The support material may be coated sufficiently thick such that therelief structure itself is over-coated with the support material. If thesupport material is sufficiently thick, it may form the substrate layerin addition to the formed portion 130 of the of the nanostructuredmaterial 100. Alternatively, a separate substrate layer may beintroduced after the support material has been applied to the masterdrum. If a separate substrate layer is used it can be any thin flexiblematerial such as a polyethylene terephthalate (PET) film, polyethylenenaphthalate (PEN) film, polyester film, polyimide film or a thin metalfoil such as aluminum foil or copper foil.

FIG. 2 shows the lamination of carrier film 110 to the support materiallayer 261 on the master drum by a nip roll 280 to form the substratelayer of the nanostructured material 100.

In the case where the support material is a thermoset material, a curingstation 270 is located adjacent to the nip roll 280 to cure the supportmaterial. If the support material 260 is a UV curable material, thecuring station 270 may include a UV radiation source such as a UV lightbulb (e.g. ELC-500 UV/Visible Curing Chamber available from Electro-LiteCorporation, Danbury, Conn.), a UV laser (e.g. an Innova Sabre FReDLaser available from Coherent, Inc., Santa Clara, Calif.), or a UV LED.If the support material 260 is a thermally curable material, the curingstation 270 may include an oven, an infrared lamp or other heat source.If the support material 260 is a thermoplastic polymer, no curingstation is required.

One function of the support material is to bind the electro-depositedportion to the substrate layer. The adhesion of the support material 260to the deposited portion should be much stronger than the adhesion ofthe deposited portion 213 to the surface 211 of the master drum 210.This enabled the removal of the nanostructured material 100 from themaster drum 210 as the master drum rotates.

An alternative fabrication system 500 utilized to perform the continuousfabrication of an exemplary nanostructured material 100 having micronand submicron features is shown in FIG. 7. The fabrication system 500includes a textured master belt 510, having a relief pattern 512 formedthereon. The master belt is generally a band of material made of anelectrically conductive material (i.e. metal) or having an electricallyconductive layer between the relief pattern and a support substrate. Therelief pattern on the surface of the master belt may be formed ofnon-conductive or dielectric material such as a non-conductive polymer,silicon dioxide, or a non-conductive carbon layer and is the negativeimage of the nanostructured material being produced. For example, if thedesired pattern on the final nanostructured material 100 is periodicdots, then the relief structure on the surface of the master belt isperiodical holes. In an exemplary embodiment, the master belt is made ofa material with good electrical conductivity such as an aluminum foil orother metal foil. Alternatively, the master belt may have anelectrically conductive material coated onto a dielectric substrate. Forexample, an ITO (Indium Tin Oxide) layer may be coated on the outersurface of a strip of PEN or PET film or the belt may be made of a pieceof metallized polyimide film (e.g. a copper clad polyimide film) whichhas been formed into a belt after the relief pattern has been formed.

The master belt drum may be mounted on a series of rollers 580, 581 suchthat a portion of the belt passes through a coating bath 530. Thesurface 511 of the master belt may be electrically charged by connectingroller 581 to the cathode 542 of a DC power source 546 in the case wheremaster belt is formed on a metallic foil and roller 581 is conductive.Inside the coating bath, an anode 544 is connected to the same DC powersupply, to form a complete electrical circuit. If a metal claddielectric film is used as the substrate for the master belt, thecathode is designed to contact the metallized surface of the belt.

The coating bath 530 contains an electrodepositable coating material 535in a carrier solution such as water. The electrodepositable coatingmaterial may be a metallic plating solution or a dispersion of anelectrically conductive oligomer or polymer. Electrodeposited metals caninclude gold, silver, tin, copper, nickel, tungsten, vanadium andvarious metallic coatings.

The electrodepositable coating material is electrolytically deposited onto the surface 511 of the master belt in the openings in the reliefpattern as the master belt sweeps through the coating bath. Preferably,the coating material does not deposit onto the surface 514 or sides 515of the dielectric relief pattern 512 on the surface of the master belt510. The thickness of the coating will increase with the residence timeof the master belt in the coating bath 530.

As the drum rotates, the deposited portion 513 will exit the coatingbath. A nozzle or spray (not shown) will rinse any residual coatingmaterial from the master drum. The cleaned portion of the coating drummay be dried by exposure to heat and/or blowing air.

A carrier film 110 may be supplied by another set of rollers 585. Alayer of support material 561 is applied onto the carrier film 110. Thelayer of support material can be added, for example, by coating,lamination, deposition, printing, or any other techniques known to thoseskilled in the art. Exemplary coating techniques to add the layer caninclude, for example, solution coating, dispersion coating, hot-meltcoating, knife coating, and dip coating. Lamination can include, forexample, heat lamination, photochemical lamination, and also can includearticle modification of the substrate or the layer or both.Post-lamination annealing can be done, if desired, to enhance adhesion.

The support material may be a thermoplastic polymer that flow atelevated temperatures but not at lower temperatures such as roomtemperature or a thermosetting resin that can be cured using a catalyst,heat, or photoexposure depending upon its chemistry. FIG. 7 illustratesa fabrication system that uses a photo-cured thermosetting resinchemistry.

The metal coated master belt and the support material are pressedtogether in a nip between rollers 580 and 585. Once the support materialhas filled in the relief pattern on the surface of the master belt it iscured by shining ultraviolet light 570 through the back side of thecarrier film to cure the support material. The electro depositedportions 513 will be removed from the master belt when the carrier filmand support material are separated from the master belt to form thenanostructured material 100.

While the processes above described above depict continuous processesfor fabricating conductive nanostructures on a flexible sheet, oneskilled in the art would recognize that these structures may also beprepared by a batch process if a master tool in the form of a texturedtile were used.

EXAMPLES Example 1

A nanostructured material 100′ having a sub-micron hole array structurewas prepared utilizing the fabrication method previously described.FIGS. 3A-3G show a flow diagram of the fabrication method by which thenanostructured material 100′ was formed.

Preparing the Master

A thin layer of a positive UV5 photoresist 306 (available from Rohm andHaas Electronic Materials, Marlborough, Mass.) was applied to a glassmaster 300 having a conductive ITO surface layer 304 with a thinchromium tie layer (not shown) between the glass layer 302 and the ITOlayer 304 as shown in FIG. 3A. The relief pattern 310 was made byinterference lithography using a Innova Sabre FReD UV laser with anoutput of 270 mW (available from Company Coherent located at SantaClara, Calif.) to pattern the photoresist layer 306 with an array ofposts 314 (FIG. 3B). The exposed areas were then removed using adeveloping solution to dissolve the undesired photoresist.

The diameter, D, of the nanostructures of the post is about 0.85 μm asshown in FIG. 3B. The pitch, P, of the nanostructures was 1.7 μm. Thisphoto resist based structure was used as dielectric material basedsub-micron structure mold.

Creating the Replicate

A thin layer of gold 320 was electrodeposited onto the surface 311 ofthe ITO glass coated master 300 in the area 316 around posts 314 of therelief pattern 310. The gold was electrodeposited using ACR 150 GoldPlating Solution available from Technic, Inc., Cranston, R.I., with acurrent density of 1 amp per square foot, and a temperature of 48° C. toyield a 0.2 μm gold layer.

A layer of a UV curable support material 330 was coated over the reliefpattern 310. The sample was placed in a vacuum chamber to prevent airentrapment in the area 316 around posts 314 of the relief pattern 310between the deposited gold layer 320 and the support material 330. TheUV curable support material was prepared in a manner similar to thatdescribed in U.S. Pat. No. 7,074,463 (examples 1A and 1B, hereinincorporated by reference) except that a mixture of 48 parts Sartomer295 (Pentaerythritol tetraacrylate monomer, available from Sartomer Co.,Exton, Pa.), 35 parts RDX-51027 (2,2′,6,6′-Tetrabromobisphenol Adiacrylate, available from Cytec Surface Specialties, Smyrna, Ga.) and17 parts Sartomer 339 (Pentaerythritol tetraacrylate monomer, availablefrom Sartomer Co., Exton, Pa.). The final SiO₂ loading was 40% by wt.instead of 37.33%. The thickness of support material applied was 200 μm.

A PEN carrier film 340 was applied to the back side of the supportmaterial 330 prior to curing the support material.

The support material was cured by subjecting the coated glass master to350 nm UV radiation 355 for 10 minutes in a nitrogen atmosphere.

The nanostructured material 100′ was removed from the glass master 300and cleaned with methanol. As shown in FIG. 4, the resultingnanostructured material had a gold surface and an array of sub-micronholes that extended through the gold surface and into the supportmaterial layer.

Example 2

A second replication master was made with a durable diamond-like carbon(DLC) relief structure on the surface of an ITO glass coated siliconmaster. A 200 nm DLC film was vacuum coated onto the surface of the ITOglass followed by application of a thin layer (about 50 nm) diamond-likeglass (DLG) as described in U.S. Pat. Nos. 5,888,594; 6,015,597; and6,696,157; herein incorporated by reference. A layer of photo resist(UV5 photoresist 306, available from Rohm and Haas Electronic Materials,Marlborough, Mass.) is applied to the to the DLG surface. The photoresist was patterned using interference lithography as generallydescribed in U.S. Pat. No. 7,085,450, herein incorporated by reference.A 3-step reactive ion etching process utilizing perfluoropropane (C₃F₈),oxygen and argon gases was used to transfer the pattern from thephotoresist into the DLC layer so that the surface of the ITO glass wasexposed in selected areas. FIG. 5 shows a schematic cross-section of thesilicon master 400 having an aluminum coated silicon base substrate 410having a conductive ITO glass layer 420 disposed on the aluminum layer412 and a DLC relief pattern 430 disposed on the ITO glass layer 420.Advantageously, the ITO glass serves as a release coating to allow theeasy removal of the electrodeposited material from the master drum.Additionally, the low-surface energy of the DLC and DLG also providedimproved release characteristics for removing cured replicated materialand the deposited material from the replication master.

A thin layer of gold was electrodeposited onto the surface 411 of thesilicon master 400 in the holes 434 of the relief pattern 430. The goldwas electrodeposited using ACR 150 Gold Plating Solution available fromTechnic, Inc., Cranston, R.I., with a current density of 1 amp persquare foot, and a temperature of 48° C. to yield a 0.2 micron goldlayer.

A layer of a UV curable support material, described above, was coatedover the relief pattern 430. The sample was placed in a vacuum chamberto ensure that there as no air trapped in the holes 434 of the reliefpattern 430. The thickness of support material applied was 200 μm.

A PEN carrier film was applied to the back side of supporting materialprior to curing the support material.

The support material was cured subjecting the coated glass master to 350nm UV radiation for 10 minutes in a nitrogen atmosphere.

The nanostructured material was removed from the silicon master andcleaned with methanol.

FIG. 6A shows an atomic force micrograph of the resulting nanostructuredmaterial having a gold surface and an array of sub-micron holes thatextended through the gold surface and into the dielectric layer. FIG. 6Bshows a scanning electron micrograph of the resulting nanostructuredmaterial. Auger electron spectroscopy confirmed that the gold was onlyon the surface of the nanostructured material and that there was no goldin the hole area of the material. The period of the microstructure is1.7 μm. The depth of the holes is about 0.6 μm.

Advantages of the disclosed method include providing reducing materialscrap and producing a nanometer-scale pattern on a large flexiblesubstrate surface for use in applications such as polarizing films forliquid crystal displays or electromagnet shielding for PDP displays.This replication method does not require lift off or reactive ionetching of unwanted material thus simplifying manufacture and reducingthe cost of the resultant film. The electrodepositable material isdeposited where it is needed, and thereby minimizing the waste of thematerial.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1. A method of making a surface structured article comprising: providinga textured master including a relief pattern formed on a surface of aconductive substrate, wherein the relief pattern is at least one of amicroscale relief pattern and a nanoscale relief pattern; immersing aportion of the textured master into a coating bath comprising anelectrodepositable material; depositing the electrodepositable materialonto the textured master; contacting a support material to the texturedmaster; and removing the electrodepositable material from the texturedmaster when the support material is separated from the textured master.2. The method of claim 1, wherein the relief pattern comprisesconductive regions and nonconductive regions.
 3. The method of claim 2,wherein the electrodepositable material is deposited on the conductiveregions of the relief pattern.
 4. The method of claim 1, wherein thetextured master is a cylindrical master drum.
 5. The method of claim 1,wherein the textured master is a master belt.
 6. The method of claim 1,wherein the textured master is a master tile.
 7. The method of claim 3,further comprising rinsing and drying a portion of the textured masterhaving the electrodepositable material coated on the conductive regions.8. The method in accordance with claim 1, further comprising applying acurrent between the coating bath and the textured master.
 9. The methodin accordance with claim 1, further comprising applying a carrier filmto a surface of the support material.
 10. The method in accordance withclaim 1, wherein the support material is a thermoplastic polymer. 11.The method of claim 8, wherein thermoplastic polymer is one of apolyolefin polymer, an ethylene copolymers, a fluoropolymer, apolyketone, a polyamide, a polycarbonate, a polyester, a styrene blockcopolymers, and styrene acrylonitrile polymer.
 12. The method inaccordance with claim 1, wherein the support material is a thermosettingresin.
 13. The method of claim 12, wherein curable resin is one of anacrylate, a polydimethylsiloxane, a urethane acrylate and an epoxy. 14.The method of claim 12, further comprising the step of curing thecurable resin.
 15. The method in accordance with claim 1, wherein theelectrodepositable material is a conductive material.